FORM 4 -------------------------- OMB APPROVAL -------------------------- OMB Number.......3235-0287 Expires: December 31, 2001 Estimated average burden hours per response.....0.5 -------------------------- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(f) of the Investment Company Actof 1940 [_] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instructions 1(b). -------------------------------------------------------------------------------- 1. Name and Address of Reporting Person Constance, Thomas E. 919 Third Avenue 41st Floor New York New York 10022 -------------------------------------------------------------------------------- 2. Issuer Name and Ticker or Trading Symbol Siga Technologies, Inc. ("SIGA") -------------------------------------------------------------------------------- 3. IRS or Social Security Number of Reporting Person (Voluntary) -------------------------------------------------------------------------------- 4. Statement for Month/Year SEPTEMBER 2001 -------------------------------------------------------------------------------- 5. If Amendment, Date of Original (Month/Year) -------------------------------------------------------------------------------- 6. Relationship of Reporting Person(s) to Issuer (Check all applicable) [x] Director [ ] 10% Owner [_] Officer (give title below) [_] Other (specify below) -------------------------------------------------------------------------------- 7. Individual or Joint/Group Filing (Check Applicable Line) [x] Form filed by One Reporting Person [_] Form filed by More than One Reporting Person ----------------------------------------------------------------------------------------------------------------------------------- Table I -- Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned | -----------------------------------------------------------------------------------------------------------------------------------| 1. Title of Security |2. |3. |4.Securities Acquired (A) |5.Amount of |6.Dir |7.Nature of Indirect | | Transaction | or Disposed of (D) | Securities |ect | Beneficial Ownership | | | | | Beneficially |(D)or | | | | | | | A/| | Owned at |Indir | | | Date |Code|V| Amount | D | Price | End of Month |ect(I)| | -----------------------------------------------------------------------------------------------------------------------------------| -----------------------------------------------------------------------------------------------------------------------------------| Common Stock |09/19/01| P | | 16,267 | A | (1) | 253,467 | D | | -----------------------------------------------------------------------------------------------------------------------------------| | | | | | | | | | | -----------------------------------------------------------------------------------------------------------------------------------| | | | | | | | | | | -----------------------------------------------------------------------------------------------------------------------------------| | | | | | | | | | | -----------------------------------------------------------------------------------------------------------------------------------| | | | | | | | | | | -----------------------------------------------------------------------------------------------------------------------------------| Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. * If the form is filed by more than one reporting person, see Instruction 5(b)(v). (Over) SEC 1474 (7-96) Page 1 of 2 ----------------------------------------------------------------------------------------------------------------------------------- Table II -- Derivative Securitites Acquired, Disposed of, or Beneficially Owned | -----------------------------------------------------------------------------------------------------------------------------------| 1.Title of |2.Con- |3. |4. |5.Number of De |6.Date Exer |7.Title and Amount |8.Price|9.Number |10.|11.Nature | Derivative |version |Transaction | rivative Secu |cisable and | of Underlying |of Deri|of Deriva |Dir|of In- | Security |or Exer | | | rities Acqui |Expiration | Securities |vative |tive |ect|direct | |cise | | | red(A) or Dis |Date(Month/ | |Secu |Securities |(D)|Beneficial| |Price of| | | posed of(D) |Day/Year) | |rity |Benefi |or |Ownership | |Deriva- | | | |Date |Expir | | |ficially |Ind| | |tive | | | | A/|Exer- |ation | Title and Number| |Owned at |ire| | |Secu- | | | | | D |cisa- |Date | of Shares | |End of |ct | | |rity |Date |Code|V| Amount | |ble | | | |Month |(I)| | -----------------------------------------------------------------------------------------------------------------------------------| -----------------------------------------------------------------------------------------------------------------------------------| Stock Option | | | | | | | | | Common | | | | | | (Right to buy) | $2.50 |08/15/01| A |V| 225,000 | A |08/15/01| 05/03/11| Stock | 225,000| | 225,000 | D | | -----------------------------------------------------------------------------------------------------------------------------------| Warrant | | | | | | | | | Common | | | | | | (Right to buy) | $3.552 |09/19/01| P | | 12,200 | A |09/19/01| 09/19/08| Stock | 12,200| (1) | 12,200 | D | | -----------------------------------------------------------------------------------------------------------------------------------| | | | | | | | | | | | | | | | -----------------------------------------------------------------------------------------------------------------------------------| | | | | | | | | | | | | | | | -----------------------------------------------------------------------------------------------------------------------------------| Explanation of Responses: (1) Mr. Constance purchased 16,267 shares of Common Stock and Warrants to purchase up to 12,200 shares of Common Stock for an aggregate purchase price of $50,000. /s/ Thomas E. Constance -------------------------------- ** Signature of Reporting Person October 10, 2001 ------------------------ Date ** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a). Note: File three copies of this Form, one of which must be manually signed. If space provided is insufficient, see Instruction 6 for procedure. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number. SEC 1474 (7-96) Page 2 of 2